CompTIA Network+ Lab Series Network Concepts. Lab 2: Types of Networks

Transcription

1 CompTIA Network+ Lab Series Network Concepts Objective 1.5: Identify common TCP and UDP default ports Objective 1.6: Explain the function of common networking protocols Document Version: otherwise noted, is licensed under the Creative Commons Attribution 3.0 Unported License. Development was funded by the Department of Labor (DOL) Trade Adjustment Assistance Community College and Career Training (TAACCCT) Grant No. TC A-48; The National Information Security, Geospatial Technologies Consortium (NISGTC) is an entity of Collin College of Texas, Bellevue College of Washington, Bunker Hill Community College of Massachusetts, Del Mar College of Texas, Moraine Valley Community College of Illinois, Rio Salado College of Arizona, and Salt Lake Community College of Utah. This workforce solution was funded by a grant awarded by the U.S. Department of Labor's Employment and Training Administration. The solution was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties or assurances of any kind, express or implied, with respect to such information, including any information on linked sites, and including, but not limited to accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability or ownership.

2 Contents Introduction... 3 Objective: Identifying Common Network Types and Functions... 3 Lab Topology... 5 Lab Settings Sharing Files Create a Shared File Conclusion Review Questions Share Permissions Testing the Share and Re-assigning Permissions Conclusion Review Questions Mapping a Drive Map a Drive to a Server Conclusion Review Questions Sharing Printers Sharing a Printer Conclusion Installing the Shared Printer Installing the Shared Printer on a Remote Computer Conclusion Review Questions Accessing a Web and FTP Server Accessing a Web Server Accessing an FTP Server Conclusion Review Questions

3 Introduction This lab is part of a series of lab exercises designed to supplement coursework and provide students with a hands-on training experience based on real world applications. This series of lab exercises is intended to support courseware for CompTIA Network+ certification. This lab will identify common functions of peer-to-peer and client/server networks. Students will create and access file and print shares in various ways, as well as access web and FTP resources. This lab includes the following tasks: 1. Create a Shared File 2. Testing the Share and Re-assigning Permissions 3. Map a Drive to a Server 4. Sharing a Printer 5. Installing the Shared Printer 6. Accessing a Web and FTP Server Objective: Identifying Common Network Types and Functions Networks provide many useful functions. Some of these functions include sharing resources such as files and printers. In a peer-to-peer network, the sharing of resources is controlled by each individual user and computer. While they are easy to set up and are convenient for home users, they do not scale well. Client/server networks are more complex, but provide better security and scale better for enterprise networks. Networks can also provide access to resources over the Internet, such as web and FTP sites. Key terms for this lab: Peer-to-peer network a network type where two or more computers share resources (such as files or printers) and each computer in the network is responsible for their own access and security. These networks are simpler and cheaper than client/server networks but are less efficient when many users exist or large amounts of resources need to be shared Client/server network a network where one centralized computer (called a server) controls access and security to shared resources. Other computers (called clients) connect to this central server to access shared resources Simple file sharing a wizard-based file sharing method that enables non-technical users the ability to easily share files over the network 3

4 Advanced file sharing a file sharing method used by administrators to provide more granular control of shared files over the network Universal Naming Convention (UNC) a standard for identifying shared resources over the network. The UNC path uses double backslashes to precede the computer name then single backslashes to separate the shared path to the resource. UNC names do not use drive letters to identify resources Permissions the rights granted to a user or group to access a resource New Technology File System (NTFS) the primary Windows file system. NTFS includes its own set of file/folder permissions. Line Print Terminal (LPT) the logical named assigned to the parallel port on a PC. Parallel ports were typically used to attach local printers although they have become obsolete and replaced with USB Universal Serial Bus (USB) a type of serial interface that is used to connect peripheral devices to a PC HyperText Markup Language (HTML) the language used for documents on the World Wide Web HyperText Transfer Protocol (HTTP) the protocol used to transfer web files over the Internet. HTTP uses TCP port 80 for initiating requests Universal Resource Locator (URL) the named address of a resource on the Internet Domain Name System (DNS) the protocol used to map hostnames and domain names into IP address on the Internet. DNS uses UDP port 53 for initiating requests File Transfer Protocol (FTP) the protocol used to send and receive files from another computer on the Internet. FTP uses TCP port 21 to set up the exchange process and TCP port 20 to exchange the actual data Internet Information Services (IIS) Microsoft s web server 4

5 Lab Topology 5

6 Lab Settings The information in the table below will be needed in order to complete the lab. The task sections below provide details on the use of this information. Required Virtual Machines and Applications Log in to the following virtual machines before starting the tasks in this lab: Windows 2k8 R2 Internal Windows 2k8 R2 Internal 1 password P@ssw0rd Windows 2k8 R2 Internal Windows 2k8 R2 Internal 2 password P@ssw0rd Windows 2k8 R2 Login (applies to all Windows machines) 1. Click on the Windows 2k8 R2 icon on the topology that corresponds to the machine you wish to log in to. 2. Use the PC menu in the NETLAB+ Remote PC Viewer to send a Ctrl-Alt-Del (version 2 viewer), or click the Send Ctrl-Alt-Del link in the bottom-right corner of the viewer window (version 1 viewer). 3. In the password text box, type P@ssw0rd and press enter to log in. 4. If the Initial Configuration Tasks and/or Server Manager windows appear, close them by clicking on the X in the top-right corner of the window 6

7 1 Sharing Files Networks provide many useful functions, including sharing resources such as files and printers. Sharing files over the network makes it easier for users to access and collaborate on files. It also prevents users from becoming confused when multiple copies of a file exist on many different machines. 1.1 Create a Shared File 1. Use the instructions provided in the Lab Settings section to log into the Windows 2k8 R2 Internal 2 machine, if you are not logged in already. 2. Click on Start -> Computer. Double-click on Local Disk (C:) to view the contents of the hard drive. 3. Create a new folder by clicking the New Folder button. Name the folder Share1. 4. Share the folder by first right-clicking on it. In the context menu, select Share with -> Specific People. This is considered simple file sharing. Many home users prefer this interface because it requires little technical knowledge and provides a wizard interface for the user to follow and complete the share. 7

8 5. When the File Sharing wizard appears, click the down arrow to the left of the Add button. This is where you can select additional users to share the folder with. Remember that when you are sharing folders between computers that are not part of a domain, users must have an account on each computer they wish to access. If you do not see the user account you need, this wizard provides you with the option to Create a new user Deselect this drop-down menu by clicking on another part of the File Sharing window. 6. Hover your mouse over the Administrator account name but do not click on it. A dialog box will appear showing you the full username, the current permission level and a brief description of what those permissions allow. Notice that the Administrator user currently has Read/Write permissions. These permissions allow this user to open, change and create files. Under the Permission Level heading, click the down arrow next to Read/Write. Change the permission level to Read. Hover your mouse once again over the Administrator account name. 1 What does the Read permission allow a user to do? Change the permissions back to the default of Read/Write. 7. Notice the permission for the Administrators group is Owner. The owner always has full access to a file or folder even if all permissions have been removed for all users. This prevents a file or folder from becoming widowed (existing without anyone having permission to access it or its settings). Hover your mouse over the Administrators group name to display the dialog box. Notice the owner has the same access as the Administrator user with Read/Write permissions. Also notice that there is no drop down arrow next to Owner, so you cannot change the Owner permission in this wizard. It is recommended that only an administrator with a firm understanding of the consequences change the owner 8

9 of a file or folder. Ensure that all settings are in their default state then click the Share button at the bottom of the screen. 8. Once the folder is shared, you have the option to someone the links to these shared items or copy and paste the links into another program. Notice the path listed next to the folder icon - \\W2K8R2INTERNAL2\Share1. This is known as the Universal Naming Convention (UNC) path. The double backslashes indicate the shared resource is located on the network. The next part is the computer name (W2K8R2INTERNAL2). The second backslash is followed by the shared folder name (Share1). Typing this path into the Run dialog box on another machine will cause that machine to attempt to connect to the Share1 folder. 9. Click Done to complete the wizard. You have successfully shared the Share1 folder. Leave this machine logged on, as you will need it for the next task. 9

10 1.2 Conclusion Sharing files over the network makes it easier for users to access data and collaborate. Simple file sharing is useful for users with little technical knowledge as the wizard interface makes the process easy for users. 1.3 Review Questions 1. Using the File Sharing wizard is known as what type of file sharing? 2. The creator of a file always has full access to the file regardless of other permissions. This account is also known as the of the file. 3. The path \\W2K8R2INTERNAL2\Share1 is also known as the path. 10

11 2 Share Permissions Sharing files over the network makes it easier for users to access data and collaborate. Permissions are used to control access to files. Users can be granted permission to read (view) a file and/or write (change) a file. Unauthorized users are not allowed to access the files at all. 2.1 Testing the Share and Re-assigning Permissions 1. Using the instructions in the Lab Settings section, log onto the Windows 2k8 R2 Internal 1 machine, if you are not logged in already. 2. Test the share you created in the first task. Click Start and in the Search programs and files text box, type the UNC path of the shared folder - \\W2K8R2INTERNAL2\Share1 - and press Enter. 3. A Windows Explorer window appears, displaying the empty shared folder. Notice that you were not prompted for a username/password to access the folder. The reason for this is because the credentials you entered when you logged onto the Windows 2k8 R2 Internal 1 machine are the exact same as the credentials needed to access the Share1 folder on the Windows 2k8 R2 Internal 2 machine. 11

12 4. Create a file in the Share1 folder. Right-click in the right pane of the Explorer window. In the context menu that appears, select New -> Text Document. Name the file Test1. 1. Why were you able to create the file? 5. Open the Test1.txt file by double-clicking on it. Type your name into the file and save it by clicking File -> Save. You are permitted to do so based on the permissions set for the Administrator account. 6. On the Windows 2k8 R2 Internal 2 machine, right-click on the Share1 folder and select Share with -> Specific people 7. When the File Sharing wizard appears, click the down arrow next to the Administrator account and change the permissions to Read. Click Share and Done to complete the changes. 12

13 8. Back on the Windows 2k8 R2 Internal 1 machine, open the Test1.txt file, edit it and save it once again. 2. Why are you able to save your changes even though you only allowed the read permission? 9. Close the Test1.txt file. 10. Create a new account on both machines called ShareTest. a. To do this, click on the Start menu, point to Administrative Tools and select Computer Management. b. Click the + sign next to Local Users and Groups in the left column to expand it. c. Click on the Users folder to display the current user accounts in the middle column. d. Right-click within the white space in the middle column and in the context menu select New User 13

14 e. When the New User dialog box appears, type ShareTest for the User name. Type in the Password and Confirm Password dialog boxes. Clear the check next to User must change password at next logon. Once you have verified your settings, click Create to add the user account. The account will not immediately appear once the button is clicked. You must click Close to exit the New User dialog before the account will appear. f. Complete the same steps on the other Windows 2k8 R2 Internal machine. Be sure that you use the exact same credentials when creating the second account. Once the accounts have been created, close the Computer Management dialog boxes. 11. On the Windows 2k8 R2 Internal 2 machine, right-click on the Share1 folder and select Share with -> Specific people Add the new ShareTest user to the share by clicking the drop-down arrow to the left of the Add button and selecting the ShareTest user from the list. Click the Add button to add the user to the list. 14

15 Notice that the default permission for this account is Read. Leave this as default and click Share and Done to add this user to the share. 5. Back on the Windows 2k8 R2 Internal 1 machine, log out of the Administrator account by clicking Start -> Log off. 6. Use the PC menu in the NETLAB+ Remote PC Viewer to send a Ctrl-Alt-Del (version 2 viewer), or click the Send Ctrl-Alt-Del link in the bottom right corner of the viewer window (version 1 viewer). 12. Log in as ShareTest by clicking on the username, typing the password of P@ssw0rd and pressing Enter to log in. 13. Access the Share1 folder by clicking Start and typing the UNC path \\W2K8R2Internal2\Share1 in the Search programs and files text box. 15

16 14. Open the Test1.txt file and add some text to change it. Attempt to save the edited file as the same name. 3. What error do you receive? 15. Attempt to save the file as Test2.txt. 4. What error do you receive this time? 5. Why do you receive these errors? 16. Click No to cancel the save then close all windows EXCEPT the Share1 folder. 17. The Simple File Sharing method you have been using only allows you to set Read or Read/Write share permissions. The Advanced File Sharing method will also allow you to set a special permission known as Full Control. This permission will allow a user to not only access and change all files contents, but also to change attributes such as the owner of a file or folder. a. To access the Advanced File Sharing return to the Windows 2k8 R2 Internal 2 machine, right-click on the Share1 folder and select Properties. 16

17 b. When the Share1 Properties dialog box appears, click on the Sharing tab at the top. Click the Advanced Sharing button in the middle of the dialog box. c. When the Advanced Sharing dialog box appears, notice the check in the box next to Share this folder and the Share name Share1 under the Settings heading.. These are filled in as a result of the Simple File Sharing wizard earlier. d. To access the permissions for this share, click the Permissions button. 17

18 e. In the Permissions for Share1 dialog box, you can view/edit permissions for current users or add/remove users from the share. Click on the Administrators group. Notice the current permissions are set to Full Control as all of the boxes next to the permissions are checked. This is because this group was listed as the Owner for this share. f. Click on the Everyone special identify. This identity is a group built into Windows that automatically includes all users and groups. Configure the Everyone special identity with the Change permission by checking the Deny check box for Full Control and putting a check under the Allow column for Change. Notice this also adds a check to the Read permission check box. This is the equivalent to the Read/Write permission in the Simple File Sharing wizard. g. Click OK on all open dialog boxes to save your changes to the share permissions. Leave the Share1 Properties dialog box open. 18

19 18. On the Windows 2k8 R2 Internal 1 machine, access the share once again and attempt to create a new file or folder. After giving the Everyone special identity Change permissions one would expect to be able to Read/Write to the folder, but access to a folder on a file server can be determined through two sets of permission types: the share permissions set on a folder and the NTFS permissions set on the folder. In this case the shared folder resides on an NTFS volume, which affects local access and remote access. The NTFS permissions on that volume also apply to the share folder. When both sets of permissions are applied (share and NTFS), the most restrictive permissions will be enforced. Given that we know the share permissions are set to Change but we are still not able to create new files/folders, the NTFS permissions must be preventing us from being able to do so. 19. Check the NTFS permissions on the Windows 2k8 R2 Internal 2 machine by clicking on the Security tab in the Share1 Properties dialog box. Click on the ShareTest account to display the current NTFS permissions. Notice that you have more options for permissions with NTFS. This granularity is why many administrators prefer to set permissions using NTFS instead of just using share permissions. In this example, notice that the ShareTest user only has Read, List folder contents and Read & Execute permissions. While this set of permissions will allow you to access the Share1 folder and its contents, it will not allow you to make any changes. 19

20 20. Click the Edit button. Select the ShareTest user and put a check in the box next to the Modify permission under the Allow column. Notice that checking this box also checks the Write permission. The difference between these permissions is that the Write permission allows you to change the contents of a file while Modify also allows you to change the attributes of the file. Click OK to save the changes made to the permissions for the ShareTest user. 21. Back on the Windows 2k8 R2 Internal 1 machine, attempt to create a new file or folder. This time, you are successful because all of the permissions (both share and NTFS) permit you to do so. 22. Close all open windows on both Windows 2k8 R2 Internal machines. 20

21 2.2 Conclusion Sharing files over the network makes it easier for users to access data and collaborate. Permissions are used to control access to files. Users can be granted permission to read (view) a file and/or write (change) a file. Unauthorized users are not allowed to access the files at all. 2.3 Review Questions 1. What share permission level only allows a user to view files and folders in a share? 2. What share permission level allows a user to view and change files and folders in a share? 3. If a share resides on an NTFS volume, which set of permissions take effect? 21

22 3 Mapping a Drive Another way to access shares is by mapping a drive. This is typical in client/server environments so clients don t constantly have to type in the share path to the folder. Mapped drives can also be deployed through group policy so the process is seamless to the end-user. When shares are mapped, they are associated with a drive letter in Computer (see section below) and accessed just like any other local drive on the computer. 3.1 Map a Drive to a Server 1. On the Windows 2k8 R2 Internal 1 machine, click Start and right-click Computer. In the context menu that appears, select Map network drive 2. In the Map Network Drive dialog box, the Drive: dropdown menu allows you to select the letter you want to associate with the mapped share. You can choose any available letter from A-Z. Notice that the letters already assigned to a resource are not in the list. Also, drive letters are only locally significant meaning that the letter one user chooses to map to a share does not have to be the same letter someone else chooses to map to the same share. From the dropdown list, select X: 22

23 3. The Folder textbox is where you type the share path. Enter the following in the textbox: \\W2K8R2INTERNAL2\Share1 4. The Reconnect at logon checkbox will automatically map the share every time the user logs in. If you will need to constantly access the share, this is a good option. If you are only using the share once or very infrequently, you may want to uncheck the box. For this example, leave this option checked. If you check the box for Connect using different credentials, you can specify what username/password combination you want to authenticate with. This would be useful if you were attempting to access a share on a computer where you did not have an account. In a typical client/server environment, clients will typically have a domain account that would allow them to log in on any computer. Therefore, this option could be used to access a share your account doesn t have permission to access. Since the user we are currently logged in as has permission to access the share, we will leave this box unchecked. 5. Click Finish to map the drive. An explorer window will open displaying the contents of the drive. Notice the letter at the top of the window. 23

24 6. Click Computer on the left column. Notice the mapped drive shows up just like a local drive. However, we know it is shared because 1) it shows up under the Network Location heading, 2) the icon showing a network connection and 3) the share path shows up next to the drive letter. 7. Close all open windows on the Windows 2k8 R2 Internal 1 machine. 3.2 Conclusion Another way to access shares is by mapping a drive. This is typical in client/server environments so clients don t constantly have to type in the share path to the folder. Mapped drives can also be deployed through group policy so the process is seamless to the end-user. When shares are mapped, they are associated with a drive letter in on the computer and accessed just like any other local drive on the computer. 3.3 Review Questions 1. When mapping a drive, what option will cause the drive to automatically reappear the next time you log in? 2. How can you map a drive if the user you are currently logged in as does not have access to the shared folder? 3. True or false? Mapped drives must have the same drive letter on all machines accessing the shared folder. 24

25 4 Sharing Printers Another use for networks is sharing printers. In a peer-to-peer network, this consists of installing the printer on one peer, sharing it on the network and installing it on the other peer. On a client/server network, the process is nearly the same, but permissions to the printer are centrally controlled on the server. 4.1 Sharing a Printer 1. On the Windows 2k8 R2 Internal 2 machine, click Start and select Control Panel. 2. In the Control Panel window, click on the Check Firewall Status link under the System and Security heading. 25

26 3. On the left side of the page, click on Restore Defaults. 4. You will need to click on Use recommended settings and then on the Restore Defaults Settings page click on the Restore Defaults button. Click on Yes when asked to confirm your choice. 5. An error may occur if you have stopped or disabled the Windows Firewall Service. To share printers in Windows 7 or in Windows Server 2008 R2, you must have the Windows Firewall Service enabled, which is why the previous steps are necessary before you can begin sharing the printer. 6. On the Windows 2k8 R2 Internal 2 machine, click Start and select Devices and Printers. 7. In the Devices and Printers dialog box, click Add a printer. 26

27 8. In the Add Printer wizard, choose the option Add a local printer. On a peer-topeer network, the printer will typically be connected to a local port such as LPT or USB. The printer could also have its own IP address. In this example, we will use the local LPT port so leave the default and click Next. 9. In the Manufacturer list, choose the option for Generic. Then under the list of Printers, choose the option for MS Publisher Color Printer. If you had a disk from the manufacturer, you could select the option Have Disk. With the options selected, click Next. 10. When asked which version of the driver to use, leave the default driver that is currently installed. Click Next. 11. Leave the default name and click Next. 27

28 12. Once the printer driver installs, you will be asked if you want to share the printer. Sharing the printer allows others to see the printer on the network and install it as if it were a local printer. Select the Share this printer so that others on your network can find and use it, change the default share name to MSColor and click Next. 13. Click Finish to close the wizard. If you click on the printer in the Devices and Printers dialog window, you will notice the state is shared. 14. Close all open windows on the Windows 2k8 R2 Internal 2 machine. 4.2 Conclusion Another use for networks is sharing printers. In a peer-to-peer network, this consists of installing the printer on one peer, sharing it on the network and installing it on the other peer. On a client/server network, the process is nearly the same, but permissions to the printer are centrally controlled on the server. 28

29 5 Installing the Shared Printer Now we will install the shared printer on another machine. Installing the shared printer will allow the other machine to use the printer like it was a locally attached device and have the ability to control its own access and settings. 5.1 Installing the Shared Printer on a Remote Computer 1. On the Windows 2k8 R2 Internal 1 machine, click Start and select Devices and Printers. In the Devices and Printers dialog box, click Add a Printer. 2. In the Add Printer wizard, choose the option Add a network, wireless or Bluetooth printer. 3. The wizard will attempt to locate the printer on the network but will be unsuccessful. To manually specify the printer information, click the link The printer that I want isn t listed. 4. Select the option Select a shared printer by name. In the text box, type the UNC path to the shared printer, \\W2K8R2Internal2\MSColor, and click Next. 29

30 5. After a brief moment, the printer will install and you will see a message that you have successfully added the printer. Click Next and Finish to exit the wizard. 6. In the Devices and Printer dialog box, click on the printer to highlight it. You will notice the name of the printer gives you the network location from where you installed it. You will also notice the icon next to State that shows a network connection. 7. Close all open windows on the Windows 2k8 R2 Internal 1 machine. 5.2 Conclusion Installing a shared printer will allow other machines to use the printer as if it is a locally attached device with the ability to control access and settings. Installing a printer from a print server is a similar process. A major difference is that if you are in a domain, administrators control access to the printer from the central server. They have the option to list the printer in the directory, which allows users to browse the list of printers in Active Directory and install the ones they want. Or, they have the option to deploy the printer with Group Policy. This forces the printer (and all settings) to be installed on computers that the policy applies to. Administrators have two choices when installing printers in this manner. They are Per User and Per Computer. Per User means the policy is applied to the user account and is available to user regardless of the system they log on to as long as they use their user credentials. 30

31 Per Computer means the printer will be installed to all computers the policy applies and any user with access to the system and log on and have permissions to use the printer. Administrators can choose one or both options. The choices can be made through the Print Management console. 5.3 Review Questions 1. If the Add Printer wizard is unable to automatically find your printer on the network, what do you need to do to install it? 2. True or false? Shared printers installed in a peer-to-peer network can control their own access and settings for that printer. 3. How can network administrators force a printer to be installed for a user regardless of the computer they log into? 31

32 6 Accessing a Web and FTP Server In addition to sharing resources, servers are also useful for hosting resources that many users need to access. Two very common resources that are hosted on servers are web (www) and FTP services. These services can be configured to only allow Intranet access (access only within an organization) or Internet access (access to the public). To access a web site, you need a web browser. Some examples of web browsers include Microsoft Internet Explorer, Mozilla Firefox and Google Chrome. Web browsers translate the HTML code that makes up the webpage and displays the page in a humanfriendly format. Web browsers use the default HTTP TCP port 80 to initiate requests. Web browsers also support a secure form of HTTP (called HTTPS) which uses TCP port 443 to access web pages. URLs are used in web browsers to identify resources. URLs are registered domain names that are linked to the public IP address associated with the resource. DNS servers across the Internet exchange these name-to-ip address mappings so users need only remember the name of the resource and not the IP addresses. DNS uses UDP port 53 to exchange information. Web browsers can also be used to access FTP resources. FTP sites are like having a shared folder accessible from the Internet. By default, FTP uses TCP port 21 to exchange control information and TCP port 20 to exchange data. 6.1 Accessing a Web Server 1. Access the web browser on the Windows 2k8 R2 Internal 1 machine by clicking Start and selecting Internet Explorer. 2. In the address bar, type the URL and press Enter. The IIS7 page that appears is being hosted on the Windows 2k8 R2 External machine acting as the web server. 32

33 3. If you know the IP address of the server hosting your resource, you can type this into the address bar as well. Type the IP address of the server, into the address bar and press Enter. You will notice the same IIS 7 page appears. 1. What change happened in the address bar? Notice that the browser automatically added the in front of the IP address. This is because the browser automatically assumed you wanted to use the HTTP protocol to access the resource. 33

34 6.2 Accessing an FTP Server 1. HTTP resources aren t the only resource that can be accessed via a web browser. FTP resources can also be accessed through the browser s interface. Like web sites, FTP sites can be accessed by their URL or IP address. In the Internet Explorer window, type the URL ftp.isp.com and press Enter. Notice the browser has specified the FTP protocol for you by adding ftp:// in front of the URL. It is a common practice for companies to name their FTP sites in this convention, so the browser assumes you want to access the site using this protocol. You will also notice that you now get a directory listing of the files on the root of the FTP server. These sites make it easy for companies to share files across the Internet. Click on the FTP Test Document. The contents of the text file are displayed. 2. It does not matter which URL you use to access the resource as long as they are all mapped to the same IP address. Try the following URLs in the Internet Explorer window and see which site comes up. Pay close attention to how you are typing the URL so you can understand why you get the appropriate site: The IIS7 page (http site) ftp:// The FTP root The IIS7 page (http site) ftp://ftp.isp.com The FTP root Each of these URLs point to the same server, so by specifying the protocol you can control what resources you access from the server. 3. Close all open windows on the Windows 2k8 Internal 1 machine. 34

35 6.3 Conclusion Servers are useful for hosting resources that many users need to access. Two very common resources that are hosted on servers are web (www) and FTP services. These services can be configured to only allow Intranet access (access only within a corporation) or Internet access (access to the public). To access a web site, you need a web browser. Some examples of web browsers include Microsoft Internet Explorer, Mozilla Firefox and Google Chrome. Web browsers translate the HTML code that makes up the webpage and displays the page in a human-friendly format. Web browsers use the default HTTP TCP port 80 to initiate requests. Web browsers also support a secure form of HTTP (called HTTPS) which uses TCP port 443 to access web pages. URLs are used in web browsers to identify resources. URLs are registered domain names that are linked to the public IP address associated with the resource. DNS servers across the Internet exchange these name-to-ip address mappings so users need only remember the name of the resource and not the IP addresses. DNS uses UDP port 53 to exchange information. Web browsers can also be used to access FTP resources. FTP sites are similar to having a shared folder accessible from the Internet. By default, FTP uses TCP port 21 to exchange control information and TCP port 20 to exchange data. 6.4 Review Questions 1. What protocol is used to access web pages on a server? 2. What protocol is used to access files shared over the Internet? 3. What is the default port for the following protocols: a. HTTP: b. HTTPS: c. FTP: d. DNS: 35